You want Windows on the SSD. You would be massively downgrading by installing Windows on a mechanical hard drive and taking it off the SSD. What you want a hard drive for is storage. Move all your data, music, movies ,pictures ect. to the hard drive and leave the OS and your programs on the SSD.
this is what i wanted to advice you too.
leave windows and other time critical software (games, some programs, drivers) on your SSD and use your HDD as a data storage for videos, music and backups.